I use solar filter made from Baader Astrosolar film (photo edition). It produces bright image of Sun and requires additional filtering. Normally I use neutral 1.25" Moon filter, sometimes dense color filters, but recently found that narrow OIII filter (Astronomik) provides image of Sun surface with better resolution. I can catch granulation pattern, filaments in shadow of spot. I guess it filters out rest of chromatic aberrations of my ED-doublet.

Superb drawings, Ernest! Absolutely wonderful! I too was amazed when I read that you're also using an OIII filter. But seeing your explanation it makes sense indeed. I hope to see a lot more of your work!